So the gist of what I got from this thread is as follows.

1 mechanic is actually more annoying to me as a brd/mch than other jobs so I want a skill to negate it. We'll just ignore that all the other jobs are annoyed by mechanics I do not have to care about as a brd/mch.

As someone mentioned earlier this is likely intentional by design, with the amount of mobility brd/mch has as a ranged dps it isn't hard to position in order to minimize or negate the effect of most knockback mechanics.